Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-12-2015, 02:14 PM   #1 (permalink)
prr
EcoModding Lurker
 
Join Date: Oct 2015
Location: CA
Posts: 31

Highlander - '06 Toyota Highlander Limited 4WD
Thanks: 1
Thanked 3 Times in 3 Posts
Why no fast acceleration?

I have just started reading some articles about fuel efficient driving. While I cannot say that I am committed to doing everything that hypermilers seem to do, I have already started backing off my speeds, and staying more off the gas pedal when I see that I need to break up ahead; in just a few days I am now automatically picking out ideal points from which I can coast. I am surprised by how much I’m enjoying this—its almost as if I’m working at a puzzle or something. It sure is making me a safer driver. And a more relaxed one--as well as saving some gas and $.

OK—down to my question. I saw one suggestion, that urged drivers not to accelerate too quickly. What is the reason for not accelerating too quickly? Is it simply that a rapid acceleration chews up more gas than a slower one? Or is it that a rapid acceleration will make it more likely that you will have to break soon?

For example, if I have a clean shot for 1/2 mile—no lights or cars ahead of me or anything—would I still be consuming gas unnecessarily by accelerating rapidly?

  Reply With Quote
The Following User Says Thank You to prr For This Useful Post:
skyking (04-18-2016)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-12-2015, 02:41 PM   #2 (permalink)
UFO
Master EcoModder
 
UFO's Avatar
 
Join Date: Sep 2010
Location: Denver, CO
Posts: 1,300

Colorado - '17 Chevrolet Colorado 4x4 LT
90 day: 23.07 mpg (US)
Thanks: 315
Thanked 178 Times in 138 Posts
If you accelerate too quickly the fuel mixture will be enriched to prevent detonation, either by the carburetor acceleration pump or by the ECU operating off its load map. When the mixture drops to 14.7:1 or lower, the engine efficiency drops.
__________________
I'm not coasting, I'm shifting slowly.
  Reply With Quote
The Following User Says Thank You to UFO For This Useful Post:
mcrews (01-20-2016)
Old 10-12-2015, 02:54 PM   #3 (permalink)
Rat Racer
 
Fat Charlie's Avatar
 
Join Date: May 2011
Location: Route 16
Posts: 4,067

Al the Third, year four - '13 Honda Fit Base
Team Honda
90 day: 42.9 mpg (US)
Thanks: 1,724
Thanked 1,861 Times in 1,208 Posts
Don't let "don't accelerate too quickly" confuse you into thinking it means "accelerate slowly." It means not to so it too quickly.

Harder acceleration means less acceleration, and that's a good thing- until the computers decide to start dumping extra fuel into the mix.
__________________

Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

  Reply With Quote
The Following 2 Users Say Thank You to Fat Charlie For This Useful Post:
mcrews (01-20-2016), skyking (04-18-2016)
Old 10-12-2015, 03:18 PM   #4 (permalink)
prr
EcoModding Lurker
 
Join Date: Oct 2015
Location: CA
Posts: 31

Highlander - '06 Toyota Highlander Limited 4WD
Thanks: 1
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by Fat Charlie View Post
Don't let "don't accelerate too quickly" confuse you into thinking it means "accelerate slowly." It means not to so it too quickly.

Harder acceleration means less acceleration, and that's a good thing- until the computers decide to start dumping extra fuel into the mix.
OK--I realize each car/engine might be different, but are there some decent rules of the thumb---like take 5 seconds for accelerating each additional 10 MPH, or something like that? Articles discussing this have been incredibly detailed---a bit too much for my eyes, given that I'm not a mechanic or a physicist.
  Reply With Quote
Old 10-12-2015, 03:26 PM   #5 (permalink)
prr
EcoModding Lurker
 
Join Date: Oct 2015
Location: CA
Posts: 31

Highlander - '06 Toyota Highlander Limited 4WD
Thanks: 1
Thanked 3 Times in 3 Posts
Let's keep it simple. I found this quote in another thread here:

It's been debated back and forth as fas as what rate of acceleration is best. Personaly, I've found it hard to notice a difference either way. What really kills your mileage is unecessary acceleration. Hard acceleration is generally thought of as bad becuase, in many cases, people accelerate hard only to have to brake hard at the stop that's right up ahead. It's really the braking that is wasting all the energy.

If this is the best policy to take, then the only thing I need to worry about is speeding up so fast that 5 secs later I'm breaking. Was that advice (in the quote) on target?
  Reply With Quote
Old 10-12-2015, 03:27 PM   #6 (permalink)
EcoModding Lurker
 
BenArcher006's Avatar
 
Join Date: Dec 2014
Location: Quebec Canada
Posts: 47

Slowpoke - '06 Saturn Vue Base
90 day: 22.88 mpg (US)
Thanks: 4
Thanked 12 Times in 7 Posts
Haha, I startrd hypermiling the same way as you. Not to commited and now I try to find every way possible to ecomod my truck so I'll get better gas millage.

Best thing to have to get the best possible gas millage without heavy ecomods, just start with a Vacuum gauge. With it you'll know if you're accelerating to hard or to soft. There is the Ultragauge that is pretty awesome to monitor your car's efficiency.
__________________

  Reply With Quote
Old 10-12-2015, 03:53 PM   #7 (permalink)
Hypermiler
 
PaleMelanesian's Avatar
 
Join Date: Dec 2007
Location: Texas
Posts: 2,314

PaleCivic (retired) - '96 Honda Civic DX Sedan
90 day: 69.2 mpg (US)

PaleFit - '09 Honda Fit Sport
Team Honda
Wagons
90 day: 44.06 mpg (US)
Thanks: 605
Thanked 422 Times in 277 Posts
High rpm acceleration is bad and consumes lots of gas. If you have a manual transmission you can do decent acceleration at not-high rpm, like 2000. If you press the pedal that same amount in an automatic it will push the rpm higher and consume more fuel. You can accelerate efficiently faster in a manual than an automatic.

High-throttle enrichment varies widely from car to car. Some you have to actually have the pedal to the floor and high rpm, like 4000+. Some cars, anything above 80% throttle will enrich the mix. So to be safe, I'd say keep the gas pedal at or below 3/4 if you don't know otherwise.
__________________



11-mile commute: 100 mpg - - - Tank: 90.2 mpg / 1191 miles
  Reply With Quote
The Following 2 Users Say Thank You to PaleMelanesian For This Useful Post:
digital rules (10-13-2015), mcrews (01-20-2016)
Old 10-12-2015, 04:05 PM   #8 (permalink)
prr
EcoModding Lurker
 
Join Date: Oct 2015
Location: CA
Posts: 31

Highlander - '06 Toyota Highlander Limited 4WD
Thanks: 1
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by PaleMelanesian View Post
So to be safe, I'd say keep the gas pedal at or below 3/4 if you don't know otherwise.
That's a nice rule of the thumb. Both vehicles are automatic. I'll try to get that in a sig on the left if I can figure out how.
  Reply With Quote
Old 10-12-2015, 04:13 PM   #9 (permalink)
Master EcoModder
 
Join Date: Jan 2011
Location: Iowa
Posts: 1,141

Impala FFV - '10 Chevy Impala LT
90 day: 29.54 mpg (US)

XFE Coupe - '09 Chevy Cobalt XFE
Team Chevy
90 day: 37.71 mpg (US)

Penny's Rogue - '15 Nissan Rogue SL AWD
90 day: 29 mpg (US)

Cam's Rogue - '11 Nissan Rogue SV AWD
90 day: 28 mpg (US)

Elantra - '17 Hyundia Elantra SE
Team Hyundai
90 day: 3.39 mpg (US)

Cruze Limited - '16 Chevy Cruze Limited LT
90 day: 38 mpg (US)
Thanks: 279
Thanked 217 Times in 184 Posts
I got best MPG with the Stratus using lots of throttle till 2500 rpm, let off to get it to shift and reapply the throttle as hard as I could without causing a down shift.

Slow accelerating with a auto tranny hurts as the torque convertor won't lock up in most cars until they shift into drive.
  Reply With Quote
The Following 2 Users Say Thank You to roosterk0031 For This Useful Post:
Joggernot (10-13-2015), UFO (10-12-2015)
Old 10-12-2015, 11:32 PM   #10 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 4,042

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 23.4 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 45.37 mpg (US)
Thanks: 1,839
Thanked 1,707 Times in 1,093 Posts
Look up "BSFC charts". Most automotive engines are most efficient at lowish RPMs and high (but not 100%) loads. As others have said, the computer will often enrich the fuel mixture as you near 100% load, which is bad. In my 5MT, I get the best economy when I shoot for about 80% load (as reported by the computer) at less than 2500RPM. The pedal position required to accelerate at that load changes based on RPM, however, so you can't just rely on pushing it a set amount. You really need instrumentation to get close to "perfection ", but I figure a good rule in an automatic is to accelerate at near the max rate you can without causing a downshift, and let it upshift as soon as possible.

That said, so long as you aren't revving it up, the biggest gains are too be found in the art of slowing down.

  Reply With Quote
The Following 3 Users Say Thank You to Ecky For This Useful Post:
PaleMelanesian (10-13-2015), ptjones (11-05-2015), UFO (10-13-2015)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com